Process for making shot



Patented Nov. 6, 1951 PaocEssroR MAKING .sno'r -Milo J. Stutzman', Kansas City, Mo., assignor to Olin Industries, Inc., East Alton, 111., a corporation of Delaware No Drawing. Application September 10, 1948, Serial No. 48,770

3 Claims. (oils-47.2)

This invention relates to the manufactureof ammunition and, more particularly, to a method of manufacturing ferrous shot.

In the commonly used drop-forming method of making iron shot, the globules of molten metal are allowed to fall in air where the globules assume a spherical shape before they fall into a tank of water, while still intensely hot, where they become solidified. During the exposure j to air and water vapor, the surfaces of the globules are subjected to oxidation. Iron shot coated with iron oxide cannot be used for some industrial applications and, specifically, a coating of oxide is objectionable because of its abrasiveness when the shot is intended for use as ammunition.

It is, therefore, an object of this invention to provide an improved method overcoming the above-noted disadvantages.

A principal object of the invention is to produce iron shot, the surface of which is bright and free of oxide. Other objects will be apparent from the following description:

In accordance with this invention, ferrous shot with bright oxide-free surface is produced by dropping globules of molten metal through air for a limited distance and catching the globules in a body of quench liquid comprising water and an organic antioxidant which exerts a partial vapor pressure from water solutions such that the vapor, produced when the quench mixture is contacted by the molten metal globules, contains both water and the antioxidant and/or its decomposition products. In partioular, it was found that, when water soluble alcohols, ketones, aldehydes, esters, or organic acids are contained in the quench water in amounts sufi'icient to prevent the formation of a film of oxide on the falling shot, but not in such a large quantity as to cause mal-formation of the shot, bright spherical pellets are produced. Each of the componds mentioned is an oxygenated organic compound.

In particular, a body of quench liquid comprising water and approximately 1.5% to 5% of a monohydric water miscible alcohol produces the desired result. It is to be understood that all percent figures given herein are stated in percent by weight.

The shot may be initially formed by the procedure disclosed in the copending application of Robert R. I-Iancox et al., Serial No. 40,276, filed July 23, 1948, now Patent No. 2,544,678 or in any other suitable way.

The invention is further illustrated, but is not intended to be limited, by the following examples:

Example I .An aqueous mixture containing 5% methyl alcohol was used as a quench bath for molten iron pellets. After falling about 26 inches through air-and 3 feet in the quench bath, the solidified shotwascollected and found to have a bright, oxide-free surface. Few irregularities of spherical configuration were observed. Bright iron pellets. have also been produced using a fall of 32 inches in air and an aqueous quench bath containing 10% methyl alcohol, but, in contrast to results obtained with 5% alcohol, the pellets were found to contain appreciable numbers of gas cavities.

Example II Other examples Bright surfaces without mal-formation were achieved when the molten metal particles were quenched in a bath consisting of water to which had been added any of the alternative organic antioxidants as indicated in the following table:

Percent- Name age Amtnn a n Bnfmml IsopropanoL Methyl ethyl lrefrme Paraldehyde Tertiary butyl alcohol Acetic acid Ethyl acetate It has been shown in the examples that ferrous shot dropped through air with limited exposure thereto and solidified by quenching in a bath of water and an organic antioxidant, in accordance with this invention, are substantially free of surface oxide and are composed of solid metal of spherical configuration. Although the preferred antioxidant content of the quench bath is from 1.5% to 5%, it is to be understood that, when the surface as to produce irregular pellets instead of shot of spherical configuration.

Having thus described the invention, what,is claimed and desired to be secured by Letters Palt= cut is:

1. In the method of making ferrous shot}.

step comprising dropping globules of molten metal into a quench bath composed-of watercontaining an organic antioxidant'whi'ch rewrites soluble and which exerts a partial vapor pressure from water solutions, said antioxidant jfistitfifi ing not more than ten? per cent by weight of the quench bath but at least sufficient to inhibit oxidation of the surface of said globules and at most less thaii sufiici'e'fit to praduce cavities in the globules;

2. In" the method or making ferrous-shot Haying a br'ightoxide-fre'e surface,- the step confiifiris= of water containing an organic antioxidant s'electedf'r'om a group consisting of methyl alcohol; ethyl alcohol;

methyl ethyl ketone, paraldehyde, tertiary butyl alcohol, acetic acid, and ethyl acetate, said antioxidant not exceeding ten per cent by Weight of the water but being in an amount suflicient to deoxidize the surface of the shot and at most less than sufficient to produce cavities in the globules.

V 31; In the method of making ferrous shot wherein globules of molten iron are dropped through an atmosphere containing oxygen and collected in an aqueous quench bath, the improvement which comprises, said quench bath containing a monollydfi alkyl alcohol in an amount sufficient to deoxid-izethe surface of the shot but not more than five' per cent by weight of said quench bath and atmdst less than sufficient to produce cavities in'the. globules.

MILO J. STUTZMAN.

REFERENCES CITED I The following references are of record in the file 6f this paten't'f UNITIE-11) 'STATES PATENTS Number 7 Name- Date 'n a Apr. 5; 2,415,161- Camp Feb. 4'; 1947 FOR-E IGN PATENTS I Ii1'rii1o =5I v Country Date' n g 3,348 Great Bl itain I391 

1. IN THE METHOD OF MAKING FERROUS SHOT, THE STEP COMPRISING DROPPING GLOBULES OF MOLTEN METAL INTO QUENCH BATH COMPOSED OF WATER CONTAINING AN ORGANIC ANTIOXIDANT WHICH IS WATERSOLUBLE AND WHICH EXERTS A PARTIAL VAPOR PRESSURE FROM WATER SOLUTIONS, SAID ANTIOXIDANT CONSTITUTING NOT MORE THAN TEN PER CENT BY WEIGHT OF THE QUENCH BATH BUT AT LEAST SUFFICIENT TO INHIBIT OXIDATION OF THE SURFACE OF SAID GLOBULES AND AT MOST LESS THAN SUFFICIENT TO PRODUCE CAVITIES IN THE GLOBULES. 